Method of producing a magnetic head

Claim 1

A method of producing a magnetic head, comprising: (a) forming on a face of a parallelopipedonshaped block made of a high permeability ferrite a resist coating film having parallel slits therein, said slits having a pitch smaller than a track width of said magnetic head and subjecting said block to electrolytic etching with an electrolytic solution to form a corrugation having a height not les than a value of a longest wavelength of luninance signals and color signals recorded on a tape; (b) providing a layer of a magnetic alloy by sputtering on said corrugation; (c) providing grooves in the magnetic alloy and said block along an edge of said magnetic alloy layer, each of said grooves extending substantially parallel to said corrugation to define a track having a predetermined width; (d) filling said grooves with a non-magnetic material and polishing said magnetic alloy layer and said non-magnetic material in said grooves to form a mirror-like face to thereby provide a first magnetic core portion; (e) preparing a second magnetic core in accordance with steps (a)-(d), providing a groove for a coil winding on said mirror-like face of said second magnetic core portion, and providing a gap material having a predetermined thickness on said mirror-like face of at least one of said first and second magnetic core portions; (f) bonding said first and second magnetic core portions through the gap material so that the tracks of said first and second magnetic core portions abut each other, to thereby form a gap bar having a gap between the first and second magnetic core portions; and (g) severing said gap bar at a predetermined angle relative to said gap.

Claim 2

A method of producing a magnetic head, comprising: (a) forming on a face of a parallelopipedonshaped block made of a high permeability ferrite a resist coating film having parallel slits therein, said slits having a pitch smaller than a track width of said magnetic head and subjecting said block to electrolytic etching with an electrolytic solution to form a corrugation having a height not les than a value of a longest wavelength of luninance signals and color signals recorded on a tape; (b) providing a layer of a magnetic alloy by sputtering on said corrugation; (c) providing grooves in the magnetic alloy and said block along an edge of said magnetic alloy layer, each of said grooves extending substantially parallel to said corrugation to define a track having a predetermined width; (d) filling said grooves with a non-magnetic material and polishing said magnetic alloy layer and said non-magnetic material in said grooves to form a mirror-like face to thereby provide a first magnetic core portion; (e) preparing a second magnetic core in accordance with steps (a)-(d), providing a groove for a coil winding on said mirror-like face of said second magnetic core portion, and providing a gap material having a predetermined thickness on said mirror-like face of at least one of said first and second magnetic core portions; (f) bonding said first and second magnetic core portions through the gap material so that the tracks of said first and second magnetic core portions abut each other, to thereby form a gap bar having a gap between the first and second magnetic core portions; and (g) severing said gap bar at a predetermined angle relative to said gap.

Claim 4

a method of making a magnetic head, comprising: (a) forming a stepped portion by removing a part of a surface of a parallelopipedon-shaped block made of a high permeability ferrite magnetic material; (b) forming a resist coating film on said stepped portion, said film having parallel slits therein, said slits having a pitch smaller than track width of said magnetic head; (c) subjecting the ferrite block to electrolytic etching with an electrolytic solution so that a corrugation is formed at said stepped portion, said corrugation having a height greater than or equal to a value of a longest wavelength of luminance signals and color signals which are recorded on a magnetic tape; (d) forming a layer of magnetic alloy by sputtering in a predetermined thickness on said corrugation; (e) forming a track having a predetermined width by providing grooves in an edge of said stepped portion which edge includes the magnetic alloy layer, each of said grooves extending substantially parallel to said corrugation; (f) filling said grooves with a non-magnetic material and then polishing said magnetic alloy layer and said non-magnetic material to provide a mirror-like surface thereby to make a firt magnetic core so that the magnetic alloy layer remains on the stepped portion while the ferrite is exposed at portions other than said stepped portion; (g) preparing a second magnetic core in accordance with steps (a)-(f) while providing a groove for a coil winding on said mirror-like face of said second magnetic core, and providing a gap material of a predetermined thickness on the mirror-like face of at least one of the first and second magnetic cores; (h) forming a gap bar having a gap between both said first and second magnetic cores by bonding said first and second magnetic cores through surfaces between the first and second magnetic cores by use of said gap material while said tracks are butted against each other; and (i) severing said gap bar at a predetermined angle relative to said gap.

Claim 5

a method of making a magnetic head, comprising: (a) forming a stepped portion by removing a part of a surface of a parallelopipedon-shaped block made of a high permeability ferrite magnetic material; (b) forming a resist coating film on said stepped portion, said film having parallel slits therein, said slits having a pitch smaller than track width of said magnetic head; (c) subjecting the ferrite block to electrolytic etching with an electrolytic solution so that a corrugation is formed at said stepped portion, said corrugation having a height greater than or equal to a value of a longest wavelength of luminance signals and color signals which are recorded on a magnetic tape; (d) forming a layer of magnetic alloy by sputtering in a predetermined thickness on said corrugation; (e) forming a track having a predetermined width by providing grooves in an edge of said stepped portion which edge includes the magnetic alloy layer, each of said grooves extending substantially parallel to said corrugation; (f) filling said grooves with a non-magnetic material and then polishing said magnetic alloy layer and said non-magnetic material to provide a mirror-like surface thereby to make a firt magnetic core so that the magnetic alloy layer remains on the stepped portion while the ferrite is exposed at portions other than said stepped portion; (g) preparing a second magnetic core in accordance with steps (a)-(f) while providing a groove for a coil winding on said mirror-like face of said second magnetic core, and providing a gap material of a predetermined thickness on the mirror-like face of at least one of the first and second magnetic cores; (h) forming a gap bar having a gap between both said first and second magnetic cores by bonding said first and second magnetic cores through surfaces between the first and second magnetic cores by use of said gap material while said tracks are butted against each other; and (i) severing said gap bar at a predetermined angle relative to said gap.